PLT-6474: Server: Add elasticsearch/test endpoint to API. (#6792)

i18n/en.json

@@ -3503,6 +3503,14 @@
     "id": "ent.elasticsearch.start.index_settings_failed",
     "translation": "Failed to set ElasticSearch index settings"
   },
+  {
+    "id": "ent.elasticsearch.test_config.indexing_disabled.error",
+    "translation": "Elasticsearch is disabled."
+  },
+  {
+    "id": "ent.elasticsearch.test_config.license.error",
+    "translation": "License does not support Elasticsearch."
+  },
   {
     "id": "ent.emoji.licence_disable.app_error",
     "translation": "Custom emoji restrictions disabled by current license. Please contact your system administrator about upgrading your enterprise license."